Collapsible bliss-type container

ABSTRACT

A collapsible container formed of three individual blanks having at each corner an outside hingedly connected securing flange adhesively bonded to the outside surface of an adjacent side wall, and an inside securing flange adhesively bonded to the inside surface of an adjacent side wall. The securing flanges provide stacking strength. The hinge connections of the outside securing flanges are each provided in blanks for the container with spaced apart openings in the form of elongated slots to allow at least partial closing of the slots and thus relieve stress at the corner when stress is placed on the corner as the container is collapsed from set-up position.

United States Patent Stollberg et al.

COLLAPSIBLE BLISS-TYPE CONTAINER lnventors: Ray H. Stollberg, Concord; Joseph W. Leaky, Danville, both of Calif.

Crown Zellerbach Corporation, San Francisco, Calif.

Filed: Sept. 23, 1974 Appl. No.: 508,238

Related US. Application Data Continuation-in-part of Ser. No. 297,413, Oct. 13,

Assignee:

References Cited UNITED STATES PATENTS Hothersall 229/23 R 3,351,533 5/1966 Cohen 229/41 R 3,333,760 8/1967 Bridenstine 229/44 R 3,850,362 1 1/1974 Stollberg et a1 229/41 R Primary Examinerl)avis T. Moorhead Attorney, Agent, or Firm-Stanley Bialos; Corwin R. Horton; Thomas R. Lampe [57] ABSTRACT A collapsible container formed of three individual blanks having at each corner an outside hingedly connected securing flange adhesively bonded to the outside surface of an adjacent side wall, and an inside securing flange adhesively bonded to the inside surface of an adjacent side wall.'The securing flanges provide stacking strength. The hinge connections of the outside securing flanges are each provided in blanks for the container with spaced apart openings in the form of elongated slots to allow at least partial closing of the slots and thus relieve stress at the corner when stress is placed on the corner as the container is collapsed from set-up position.

4 Claims, 10 Drawing Figures PATENTEB AUG 1 2 I975 SHEET COLLAPSIBLE BLISS-TYPE CONTAINER The instant application is a continuation-in-part of applicants co-pending allowed application Ser. No. 297,413, filed Oct. 13, 1972, and discloses and specifically claims another embodiment of the invention.

BACKGROUND OF THE INVENTION This invention relates to containers of the so-called Bliss"-type, exemplified by US. Pat. No. 1,697,709 to Bliss, dated January 1, 1929, having inside and outside flanges at each corner; the flanges providing stackingstrength. Containers of the Bliss-type are formed of three units or blanks of flexible material; and in the setup container an inside flange is secured to the inside surface of an adjacent side wall of the container and an outside flange is secured to the outside surface of an adjacent wall. By virtue of the pair of upright flanges at each corner, stacking strength obtains when containers are stacked one above the other. A problem has heretofore existed in rendering these containers collapsible to substantially flat condition from their set-up position without joint separation or tearing at the corners because of stress which weakens an adhesive bond.

SUMMARY AND OBJECTS OF THE INVENTION In Applicants co-pending application, two embodiments are disclosed and claimed generically for overcoming the aforementioned problem. The instant application relates to another embodiment wherein elongated, spaced apart slots are provided in the container blank containing the hinge connection line of each outside flange. These slots are included in the hinge connection lines of such outside flanges. As a consequenee, when suitably scored so that when the container is collapsed from set-up position, each of a pair of opposite side walls project outwardly from the bottom wall with the securing flanges at a corner extending in opposite directions in substantially the same plane.

The slots in the hinge lines or connections of the outer flanges allow at least partial closing of the slots, and thus provide increased flexibility and relieve stress at the corner when stress is placed on the corner as the container is collapsed from set-up condition. If such stress were not relieved. it could cause separation of liners of corrugated paperboard or joint failure. At the same time, stacking strength of the set-up container is not sacrificed because of the two upright securing flanges still present at each corner.

Advantageously, the container blanks are each made of relatively heavy paperboard, and desirably of socalled single wall corrugated paperboard containing a single corrugating medium and a sheet of liner paper adhcsively bonded to each side or face of the corrugating medium.

From the preceding, it is seen that the invention has as its objects among others, the provision of a collapsible Bliss style container made of flexible sheet material and of three blanks or parts in which the corners have upright inside and outside securing flanges providing stacking strength, which is of improved construction to relieve stress at the corners when the container is collapsed from set-up condition, and which is of simple and economical construction.

Other objects will become apparent from the following more detailed description and accompanying draw ings, in which:

DESCRIPTION OF DRAWINGS FIG. 1 is an isometric view of the container hereof in fully set-up condition;

FIG. 1A is a similar view illustrating the container in partially collapsed condition;

FIG. 1B is a simiilar view illustrating the container in I completely collapsed condition;

FIG. 2 is a horizontal section taken in plane indicated by section line 2-2 of FIG. 1;

FIG. 3 is a plan view of a first blank or unit of material from which the container is made;

FIG. 3A is a plan view -of a second blank of such material; 2

FIG. 3B is likewise a plan view of the third blank; FIG. 4 is a perspective view of the corner construction;

FIG. 5 is a horizontal section taken in a plane indicated by line 5-5 in FIG. 4;

FIG. 5A is a section similar to FIG. 5, illustrating the corner structure when the container is in a collapsed condition.

DETAILED DESCRIPTION The container hereof is known in the trade as a Blisstype, which is formed of three individual pieces or blanks that can be readily erected to set-up position by the apparatus and method disclosed in assignee's US Pat. No. 3,659,505, dated May 2,1972. A first of such blanks, illustrated in FIG. 3, comprises a substantially center rectangular bottom wall panel 2, side wall forming panels 3 hingedly connected along score lines 4 at each of opposite edges of the bottom wall panel. Closure flaps 6 are hingedly connected to side wall forming panels 3. Hingedly connected to bottom wall panel 2 are bottom securing flanges 8. A securing flange 9 is hingedly connected by a score line 11 to each of the opposite edges of side wall panels 3. In the set-up container, these flanges 9 are upright outside securing flanges. V-shaped notches 10 are formed between the ends of adjacent flanges 8 and 9 which provide bottom abutment joints in the set-up carton.

Each hinge connection line 11 includes at least a pair of alined elongated slots 12 which result from removal of material from the blank and which are coincident with the line. Also, forming part of each hinge connection line 11 are relatively short end score lines 13 and a relatively short intermediate score line 1 4 between the slots, which form connecting bridges.

A second blank (FIG. 3A) comprises substantially rectangular side wall panel 16, a corner securing flange l7 hingedly connected to each edge of side wall panel 16 along hinge line 18, and a closure flap l9 hingedly connected thereto. To enable the container to be collapsed substantially flat, wall panel 16 is provided with a pair of triangularly arranged score lines 20, each leading from a lower corner of panel 16 with the apex of the triangle on a central score line 20'. A central score line 21 in line with score line 20' extends across closure flap 19 to the apex of the triangle formed by diagonal score lines 20. When the blank of FIG. 3A is attached to the blank of FIG. 3 in the set-up container, score lines 20, 20 and 21 permit side wall panel 16 to collapse outwardly from bottom panel 2 of the blank of FIG. 3, as can be seen from FIG. 1A and 1B.

The third blank, shown in FIG. 3B, is of the same construction as the blank of FIG. 3A, and, consequently, the same reference numerals are applied.

With reference to FIGS. 1, 1A and 1B, which illustrate the set-up container, it will be noted that the blanks are secured together with flanges 8 on bottom wall panel 2 upright and adhesively bonded to side walls 16; and the corner securing flanges 9 of side walls 3 are secured upright by adhesive bonding to the outside surfaces of side walls 16 at the corners, while flanges 17 on side walls 16 are adhesively bonded to the inside surfaces at the corners of the container side walls Thus, at each corner there are two upright or upstanding securing flange's which not only act to secure the container parts or units together, but provide stacking strength when containers containing product are stacked one on top of the other.-It is to be noted that the elongated slots 12 are relatively narrow, and are coincident with hinge connection line along which they are formed, so that the width of the flanges at the corners is substantially unaffected, and stacking strength provided by the pair of securing flanges at each corner is not impaired. One of these securing flanges at each corner is an inside flange and the other an outside flange. In collapsing thecontainers, opposite side walls 16 collapse outwardly, as is shown in FIG. 1A, and the container can be completely collapsed to substantially flat condition, as is shown in FIG. 18.

With reference to-FIGS. 5 and 5A, wherein FIG. 5 illustrates a corner construction of the set-up container, and FIG. 5A illustrates the position that adjacent walls assume in the collapsed condition, it will be noted that as wall 16 is collapsed outwardly, it assumes a position substantially in line with wall 3 of the first blank with the corner flanges 9 and 17 extending in opposite directions. As a result of such collapsing, a buckling force is exerted on the hinge connection line between outside flange 9 at each corner and side wall 3 to which it is connected. This would normally cause the hinge connecting line to bunch up or buckle with consequent possible joint failure.

However, the elongated slots 12 allow at least partial closing of the slots and thus relieve stress at the corner. Only the relatively short bridge connections l3, 14 will buckle as is shown in FIG. 5A, but the slots provide sufficicnt relief to obviate joint failure. At the same time, stacking strength is not impaired because both flanges 9 and 17 at each corner remain bonded to the adjacent side wall surface.

In this connection, slots 12 are reIatively long and bridge connecting scores 13 and 14 are relatively short. The container is initially manufactured in set-up condition annd then collapsed for shipment. For a container of about 11 inches high, two slots 12 each of about 3 7/16 inches long and about inch wide, with the middle bridge 14 about 1% inches long, and the two end bridges 13 about I A inches long, are suitable, but these dimensions may vary. Desirably, the hinge connection bridges are score lines of about 0.008 inch (8 point); and such lines are longitudinally centered with reference to the slots. Desirably, the total length of the slots should be substantially greater than the combined length of the bridges, at least one and one-half times greater.

The collapsible-type container hereof is especially adapted for the packaging of solid products, such as commodities including lettuce, and for such purposes ventilating openings 25 are provided in walls of the container. Because of its collapsible character, it is a re-usable container. It may be of any suitable size, and

- is desirably made of so-called single-wall corrugated paperboard, comprising the usual corrugating medium and two plain liner sheets adhesively bonded thereto.

In the embodiment of the invention illustrated adapted for packaging of lettuce, the stock material is heavy, B-flute, single-wall, corrugated paperboard about 3/16 inch in overall thickness and 275 pounds test. The container has an overall length of about 22 inches, an overall width of about 16 inches, and .an overall height of about 1 l inches.

We claim: 1 w

l. A blank construction for a collapsible container of flexible sheet material having score lines arranged for folding of the container to collapsed condition when empty comprising three blanks securable together; a

first of said blanks comprising a central substantially rectangular bottom wall panel, a substantially rectangular side wall panel hingedly connected to each of a pair of opposite edges of the bottom wall panel, a securing flange hingedly connected to .each of the remaining edges of said bottom wall panel, and a securing flange hingedly connected to each edge of each side wall panel; a second and third of said blanks, each com prising a substantially rectangular side wall panel and a securing flange hingedly connected to each of oppo being an outside flange for adhesive bonding to the outside surface of the adjacent side wall panel; each of the hinge connections of said outside securing flanges including spaced apart relief slots coincident with said hinge connection to allow at least partial closing of the slots and thus relieve stress at the corner when stress is placed on the corner as the container is collapsed from set-up condition.

2. The construction of claim 1 in which the outside securing flanges are on the side wall panels of said first blank and the inside securing flanges are -on the side wall panels of the second and third blanks.

3. A collapsible container of paperboard comprising. a bottom wall and pairs of opposite side walls having score lines arranged for folding of the container to collapsed condition when empty with the bottom wall of i the container and a pair of opposite walls positioned inwardly between another pair of opposite side walls,

and comprising three units having upright corner flanges adhesively bonded to the pairs of opposite walls of the container with a pair of flanges at each corner extending substantially the height of the container to provide stacking strength, one of said flanges at each corner being an outside flange overlying and adhesively bonded to the outside surface of the adjacent side wall,

and the other of said flanges at such corner being an inside flange underlying and adhesively bonded to the inside surface of the adjacent side wall; each outside flange being connected at each corner to a side wall by all a hinge connection. which includes at least two elongated spaced apart relief slots coincident with the hinge connection to allow at least partial closing of the slots and thus relieve stress at the corner when stress is placed on the corner as the container is collapsed from set-up condition, a relatively short bridge connection at the top and bottom of said hinge connection and a relatively short bridge connection between said slots. the combined length of the slots being at least one and onehalf times the combined length of the bridges.

4. A collapsible container of paperboard comprising a bottom wall and pairs of opposite side walls having score lines for folding the container to collapsed condition when empty with a pair of opposite side walls collapsed outwardly from the bottom wall, and comprising three units having hingedly connected upright corner bonded to the inside surface of the adjacent side wall,

the hinge connection line of the outside flange at each corner comprising at least two relatively narrow elongated slots unaffecting the width of the securing flange, a relatively short and narrow bridge connection between said slots, and a bridge connection at the top and at the bottom of the hinge connection to relieve stress at the corner when stress is placed on the corner as the container is collapsed from set-up condition. 

1. A blank construction for a collapsible container of flexible sheet material having score lines arranged for folding of the container to collapsed condition when empty comprising three blanks securable together; a first of said blanks comprising a central substantially rectangular bottom wall panel, a substantially rectangular side wall panel hingedly connected to each of a pair of opposite edges of the bottom wall panel, a securing flange hingedly connected to each of the remaining edges of said bottom wall panel, and a securing flange hingedly connected to each edge of each side wall panel; a second and third of said blanks, each comprising a substantially rectangular side wall panel and a securing flange hingedly connected to each of opposite edges of each of the latter side wall panels; the securing flanges on said bottom wall panel being securable to the side wall panels of said second and third blanks and the remaining securing flanges of said blanks being at the upright corners of the container when set up with a pair of flanges at each corner, one of such corner flanges being an inside flange for adhesive bonding to the inside surface of the adjacent side wall panel, and the other of said flanges at each corner being an outside flange for adhesive bonding to the outside surface of the adjacent side wall panel; each of the hinge connections of said outside securing flanges including spaced apart relief slots coincident with said hinge connection to allow at least partial closing of the slots and thus relieve stress at the corner when stress is placed on the corner as the container is collapsed from set-up condition.
 2. The construction of claim 1 in which the outside securing flanges are on the side wall panels of said first blank and the inside securing flanges are on the side wall panels of the second and third blanks.
 3. A collapsible container of paperboard comprising a bottom wall and pairs of opposite side walls having score lines arranged for folding of the container to collapsed condition when empty with the bottom wall of the container and a pair of opposite walls positioned inwardly between another pair of opposite side walls, and comprising three units having upright corner flanges adhesively bonded to the pairs of opposite walls of the container with a pair of flanges at each corner extending substantially the height of the container to provide stacking strength, one of said flanges at each corner being an outside flange overlying and adhesively bonded to the outside surface of the adjacent side wall, and the other of said flanges at such corner being an inside flange underlying and adhesively bonded to the inside surface of the adjacent side wall; each outside flange being connected at each corner to a side wall by a hinge connection, which includes at least two elongated spaced apart relief slots coincident with the hinge connection to allow at least partial closing of the slots and thus relieve stress at the corner when stress is placed on the corner as the container is collapsed from set-up condition, a relatively short bridge connection at the top and bottom of said hinge connection and a relatively short bridge connection between said slots, the combined length of the slots being at least one and one-half times the combined length of the bridges.
 4. A collapsible container of paperboard comprising a bottom wall and pairs of opposite side walls having score lines for folding the container to collapsed condition when empty with a pair of opposite side walls collapsed outwardly from the bottom wall, and comprising three units having hingedly connected upright corner flanges extending substantially the height of the container to provide stacking strength, one of the flanges at each corner being an outside flange overlying and Adhesively bonded to the outside surface of the adjacent side wall, and the other of said flanges at such corner being an inside flange overlying and adhesively bonded to the inside surface of the adjacent side wall, the hinge connection line of the outside flange at each corner comprising at least two relatively narrow elongated slots unaffecting the width of the securing flange, a relatively short and narrow bridge connection between said slots, and a bridge connection at the top and at the bottom of the hinge connection to relieve stress at the corner when stress is placed on the corner as the container is collapsed from set-up condition. 